This invention relates to x-ray detectors and more specifically relates to techniques for testing such detectors.
Almost all image quality evaluation methods rely on placing off-the-shelf or custom-made x-ray phantoms in the field of view. Some methods use image processing and analysis tools to automatically detect regions of interest in the acquired image of the phantom. These methods have a significant advantage over xe2x80x9cmanualxe2x80x9d methods that rely heavily on human operators to perform these measurements. These methods also provide more consistent and objective measurements.
However, automating the analysis of the image of the phantom does not result in full automation of the image quality evaluation, because, like the xe2x80x9cmanualxe2x80x9d methods, they still require intervention by a human operator to place the x-ray phantom(s) in the field of view. Experience has shown that human operators are not inclined to take the time to place the x-ray phantom in the field of view. As a result, detector problems may go undetected for some time. X-ray images generated while the detector problems go undetected can result in degraded image quality.
This invention addresses these problems and provides a solution.
The preferred embodiment is useful in an x-ray system comprising a digital detector defining a first region suitable for generating data useful for creating a patient x-ray image and a second region less suitable for generating such data than the first region. In such an environment, the detector can be tested by providing a source of x-rays and a phantom located between the source and at least a portion of the second region so that the detector generates detector test data in at least a portion of the second region in response to the x-rays. At least one parameter is measured in response to at least a portion the test data. A first value of the one parameter is stored at one point of time. A comparison is made of the first value with a second value of the one parameter generated at a second point in time later than the first point of time. A result signal representing the results of the comparison is generated.
By using the foregoing techniques, the detector can be tested without human intervention, thereby insuring more reliable and timely testing than has been possible in the past.